using System;

public class Program {
	public void Solve() {
		Console.ReadLine();  // N
		string[] s = Console.ReadLine().Split(' ');
		int v = int.Parse(Console.ReadLine());
		int sum = 0;
		for (int i = 0; i < s.Length; i++) {
			sum += int.Parse(s[i]);
		}
		int ans = sum - v;
		Console.WriteLine(ans);
	}
	
	public static void Main(string[] args) {
		Program program = new Program();
		program.Solve();
	}
}